Benefits of I-beams in construction

Hot-rolled steel beam having I-shaped cross section, and tapered flanges closer than wide flanged beam is known as I-beam.

I Beam contains one vertical plane and two horizontal planes or flanges which develop 'I' or 'H' structure. The vertical plane withstands the shear stress , whereas horizontal planes withstand the bending movement. I Beam is majorly utilized in construction industry like construction of manufacturing plants, multi-story buildings etc.

I-beam is frequently applied as important support trusses, or the primary framework, in buildings. Steel I beams retain structure’s integrity with persistent strength and support. The extreme power of I beams minimizes the requirement for several support structures and as a result huge time and money is saved. The stability of the structure is improved considerably.

Some vital jargons of I-Beam:

1. Flange thickness: Top and bottom horizontal plate-like segments of an I-beam are known as flange. The density of the flanges is defined as the flange thickness.

2. Flange width: The width of the flanges is known as flange width.
3. Beam depth: The height among the top and bottom surface of the steel I beam is termed as beam depth.
4. Web thickness: The vertical segment of steel I beam is known as web, and the thickness of the web is termed as web thickness.
5. Fillet radius: The curved section, where the changeover among the web and flange occurs is known as a fillet. The radius of the fillet is defined as the fillet radius.

A properly sized I Beam can be chosen on the basis of the following criterion :-

The entire method of choosing the proper size of the I beam is dependent on the basic mechanical design calculations as given below:

1. The first input necessary belongs to the steel I beam load specifications or loading details on the steel I beam.
2. Draw bending moment diagram for the specified loads and get the value of maximum bending moments (suppose M) that the steel I beam is likely to experience.
3. Select an exact size of steel I beam from a standard I beam table.
4. Determine the area moment of inertia (suppose I) of the selected steel I beam.
5. Obtain the beam depth (suppose d) of the selected steel I beam.
6. The stress developed (f) in the beam can be measured with the formula given below :

f/(d/2)=M/ I

f denotes the bending stress.
M denotes the moment at the neutral axis.
y denotes the perpendicular distance to the neutral axis.
I denotes the area moment of inertia about the neutral axis x.

7. Compare the calculated value of the bending stress with the yield stress of the steel with the purpose of verifying the safety factor of your design.

The structural design will be perfect when the size of the I-beam is accurate. The method described above is dependent on static I beam load specifications. In case where dynamic loads are concerned, it is necessary to apply FEA tools like ANSYS, Pro Mechanica, etc.

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Different components of super structure

Superstructure stands for segments of the structure that is situated over the surface of the ground. The superstructure is built with different sections of walls, roof, doors, and windows, flooring. The sections of the structure situated on the grounds and underneath the ground floor level are known as the plinth.

The objective of superstructure is to bear different types of loads operating on the structure which range from dead load, live, load, wind load etc. These loads are then transferred to the underlying soil through the substructure.

Each element of superstructure is applied as a specific purpose, but the prime function is to arrange privacy, safety to the inhabitants. Wall and roof safeguards from the surrounding, doors permit entry and give safety, windows arrange requisite sunlight and fresh air and floor provides a leveled surface to live and protection from beneath.

Building superstructure

Column: A column in structural engineering stands for a vertical structural component that disperses the weight of the structure over to other structural components underneath , through compression.

Floor: A floor normally comprises of a support structure known as a sub-floor on top on which a floor cover is placed to arrange a walking surface.

Roof wall :

Flat – Should contain a slight slope for drainage

Shed – A single slope

Gable – Two slopes intersect at a ridge. Two walls expand up to the ridge.

Hip – Two gables, a pyramid is treated as a hip roof.

Gambrel – Four slopes in one direction, the usual barn roof.

Mansard – A four-sided gambrel-style hip roof formed with two slopes on each of its sides with the lower slope, perforated by dormer windows, at a steeper angle than the upper.

Beam: Beam stands for an inflexible structural member formed to bear and transmit transverse loads across space to supporting components.



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Common structural members in a building

In this civil engineering article, you will get detail information on different types of structural members in a building.

Beam: Beam stands for a flexure member of the structure. It is exposed to transverse loading like vertical loads, and gravity loads. With these loads, shear and bending are formed inside the beam. Beams belong to horizontal structural members to bear a load successfully.

Beam is generally applied for withstanding vertical loads, shear forces and bending moments.

Columns: A long vertical member that mostly undergoes compressive loads & buckling loads is known as column. Columns stand for vertical, structural members of a structure. They transmit load from beams to footings. Columns are mostly utilized to support beams or arches on which the upper sections of walls or ceilings rest.

Strut: Strut is a compressive member of a structure. This structural member is driven from opposite ends. The purpose of a strut is to withstand compression.

Ties: A tie stands for a structural member that is extended from opposite ends. A tie mainly deals with tension.

Beam-Column: A structural member that is exposed to compression and flexure is known as beam column.

Grid: A group of beams which overlap each other at right angles and exposed to vertical loads is known as grid.

Cables and Arches: Cables are normally suspended at their ends and are granted to sag. The forces then turn to pure tension and are headed along the axis of the cable. Arches have the similarity with cables apart from they are inverted. They bear compressive loads which are directed along the axis of the arch.

Plates and Slabs: Plates belong to three dimensional flat structural components generally constructed with metal which are frequently utilized in floors and roofs of structures. Slabs are identical to plates apart from that they are normally constructed with concrete.



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POLEFDN – A excel based construction program for pole foundation analysis

POLEFDN is a MS-excel based spreadsheet program that can be used for making analysis of a pole foundation on the assumption of the application of a inflexible round pier that is supposed free (unrestrained) at the top and exposed to lateral and vertical loads. The spreadsheet particularly makes calculation for the necessary embedment depth, the maximum moment and shear, the plain concrete stresses, and the soil bearing pressures.

This program stands for a workbook that comprises of the following six (6) worksheets:

• Doc - Documentation sheet
• Pole Fdn (Czerniak) - Pole foundation analysis for free-top round piers with PCA/Czerniak method
• Pole Fdn (UBC-IBC) - Pole foundation analysis for free-top round piers with UBC/IBC method
• Pole Fdn (OAAA) - Pole foundation analysis for free-top round piers with OAAA method
• Granular Soil (Teng) - Pole foundation analysis in granular soil with USS/Teng method
• Cohesive Soil (Teng) - Pole foundation analysis in cohesive soil with USS/Teng method

Given below, some useful features of the program :-

This program can deal with both horizontally and vertically applied loads. The vertical load may contain an associated eccentricity that leads to an additional overturning moment to be always assumed to add directly to the overturning moment formed with the horizontal load.

This program guesses that the top of the pier remains at or over the top of the ground surface level.

This program guesses that the actual resisting surface remains at or under the ground surface level. It takes into account any weak soil or any soil that is detached at the top.

The "Pole Fdn(Czerniak)" worksheet guesses that the inflexible pier rotates about a point situated at a distance, 'a', under resisting the surface. The highest shear in pier is supposed to be at that 'a' distance, whereas the maximum moment in the pier is supposed to be at a distance = 'a/2'.

The "Pole Fdn(Czerniak)" worksheet works out the "plain" (unreinforced) concrete stresses, compression, tension, and shear in the pier. The corresponding permissible stresses are also set on the basis of the strength (f'c) of the concrete. It is performed to check whether the steel reinforcing is actually necessary or not. The permissible tension stress in "plain" concrete is supposed to be equivalent to 10% of the value of the permissible compressive stress.

The "Pole Fdn(Czerniak)" worksheet measures the actual soil bearing pressures along the side of the pier at equivalent distances to 'a/2' and 'L'. The relevant permissible passive pressures at those locations are set for comparison.

As all overturning loads are protected with the passive pressure against the embedment of the pier, this program guesses that the pier functions in direct end bearing to withstand only the vertical loading. The bottom of pier bearing pressure is measured that contains the self-weight of the pier, assumed at 0.150 kcf for the concrete.

To download the program, click on the following link www.cesdb.com



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Types of formworks found in construction

Generally, steel or concrete is used in formwork to build part of the permanent structure. Temporary formwork can be struck and recycled from any inexpensive and easily worked material, timber, steel and GRC/GRP.

The formwork that should be utilized under the water, should abide by the following conditions :

a. Support the concrete in its designed profile during the plastic phase
b. Properly affixed into position.
c. Cover the concrete from scour, washout and abrasion till unless it gets solidified.
d. Endure mistakes in development level or alignment of adjoining work
e. Ability to resist the static and dynamic loading caused by concrete, tides, waves and currents.

It is designed in the context of the permanent works and be abandoned in situ or as temporary works either to be abandoned in situ or smitten and recycled.

The following types of formworks are mostly found :-

Ceiling Formwork: Ceiling formwork belongs to the type of formwork commonly found in structures/buildings.

The formwork sheeting comprises of sheeting boards or prefabricated sheeting panels. The formwork sheeting is located on squared timber formwork bearers to be provided on main bearers capturing the forces to round timber columns. With smaller rooms, the main bearer along with two columns develops a trestle. Diagonal board bracings are arranged to manage horizontally acting forces. The round timber columns are arranged on double wedges which function as stripping aid and correction device.

Beam Formwork: Beam formwork contains prefabricated formwork sheeting parts (sheeting bottom and side sheeting panels). Such individual parts are erected on the basis of the beam dimensions stated in the project. For prefabrication of the formwork sheeting parts, a special preparation table should be created on site.

Column Formwork: Same as beam formworks, the sheeting of column formworks is prefabricated based on the column dimensions from sheeting boards attached with cover straps.

The sheeting panels are arranged in a foot rim which is secured in the soil with steel bolts.

The foot rim consists of double-nailed boards. The foot rim must be exactly measured-in because it is decisive for the exact location of the column. It has the same functions as the thrust-board for foundation or beam formwork.

When the sheeting panels are implanted in the foot rim, vertical arch timbers are arranged to undertake the forces from the cover straps of the formwork sheeting.

Around the arch timbers, that contains the function of walers, column clamps of flat steel are braced with wedges or a rim of boards is provided same as the foot rim. Supplementary formwork tying with tie wires or steel screws is not required.

The distances of the clamps are mentioned in the formwork project. Generally, they are roughly 700 mm.

The column in the formwork is laterally fastened by diagonal board braces.



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Design of Beam

1. Estimation of constants. -For the specified set of stresses, determine KC, JC and RC.

2. Kc= M~cbc/M~cbc+~st

3. Jc= 1-(Kc/3)

4. Rc= 0.5*L*Kc Jc

5. Estimation of bending moment. Suppose appropriate values of overall depth and breadth of beam, and find out the effective span. Work out the self-weight and total U.D.L. and maximum bending moment in the beam.

6. Design of the section. Workout the effective depth of the beam with the following expression:

7. d= [(M)/ (RC*b)] 0.5

8. Reinforcement. Workout the area with the formula.

9. Shear Reinforcement. Workout the maximum shear force in the beam.

10. Verify for Development length at the end.

11. Ld<= (M1/V) +L0.

Design of column:

1. Find out the allowable stresses in concrete, longitudinal bars and ties.
2. Determine the super impose load that should be borne by the column.
3. Find out the area from the following expression - P= ~cc *Ac+~sc*Asc.
4. After getting details about the area, find out the dimensions of column. If it is a square of side b, then b=Ag.
5. For the specified end conditions, find out the effective length of column. Measure lef/b ratio to determine whether the column is short or long.
6. If lef/b ratio<12 it will be designed as short column or else as long column; define the area of steel Asc.
7. Determine the diameters of bars utilized as ties and find out its pitch according to the rules.

DESIGN OF FOOTING: The width B of the footing will obviously be equivalent to [W+W‟]/qo. The thickness is measured based on the bending moment as well as punching shear.

1. Depth for bending moment.
d= [M/B*Rc] 0.5
2. Depth for shear.
3. tv=V/B*d
4. Steel Reinforcement. Ast=M/tjcd

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How to create the design of simply supported steel beam

This construction video is created for educational purpose.The tutorial will be a complement to the "Mechanics of Materials" course conducted at the Colorado School of Mines.By watching this construction video tutorial, one can learn how to create the design efficiently for simply supported steel beam.

Download Design of a Steel Beam in pdf

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